A water bed is simply a water filled bladder that is used as a mattress. The bladder is sometimes filled with fiber or fitted with internal channels to improve comfort. Otherwise, the interior of the mattress can be empty. Examples of known water bed assemblies are shown in U.S. Pat. No. 3,748,669 to Warner and U.S. Pat. No. 3,999,235 to Mollura.
Waterbeds must be drained in order to be moved, relocated or repaired. Typically, the water-tight bladder is fitted with one or more valves through which water is added to fill the bladder or pumped out to drain the bladder. The conventional valve is simply a threaded neck of the type shown in the Warner patent which may be capped. Currently, draining is performed through the use of an external pump that is fitted to an adapter threaded to a valve that is permanently installed in the bed. The adapter is used to convert the valve thread to a garden hose thread and to provide a swivel for ease of hose attachment. An example of such an adapter is shown in U.S. Pat. No. 4,212,335 to Bova.
FIG. 1 shows a conventional water bed mattress. The water bed mattress includes a water tight bladder 5 having a water tight interior area 50 which may be filled with water so that the bladder may be used as a mattress. As mentioned above, the bladder 5 is sometimes filled with fiber or fitted with internal channels to improve comfort, but for simplicity these are not shown. The water tight bladder may be formed of any suitable water tight material as is known in the art.
The bladder 5 includes a valve through which water can be added to or pumped from the bladder. As shown in FIG. 1, the valve is typically a neck portion formed with threads 3 or the like. The neck-type fill/drain valve 1 is typically formed separately from the water tight bladder 5 and secured thereto by heat or adhesive. The threads 3 need not be formed directly on the neck; they may be provided by attaching an adaptor or the like to the neck as is known in the prior art.
In FIG. 1 the overall size of the water filled bladder 5 is represented schematically. As is known in the art, the water filled bladder is typically mattress-sized.
In a conventional water bed, an adaptor such as that disclosed in U.S. Pat. No. 4,212,335 to Bova may be fit into an opening or threaded to the valve threads so that a garden-type hose can be attached for filling or draining. When the bladder is being drained, a pump must be used. Typically, either a venturi pump of the type disclosed in the present inventor's previous patent U.S. Pat. No. 4,810,170 or an electric pump is used. In the case of modern fiber filled mattress bladders, an electric pump can be clogged by the fiber fill. Moreover, external pumps are expensive and must be rented by the customer. Accordingly, in at least these cases, a venturi pump is preferred.
The use of venturi action for causing suction by the passage of fluid through nozzles is well known and documented. A venturi pump typically includes a water supply pipe, and an outlet pipe which is in line with the inlet pipe. Variations of this basic construction are disclosed in the present inventor's previous patent as well as in U.S. Pat. No. 857,920 to Boekel and U.S. Pat. No. 995,969 to Junk.
While venturi pumps offer advantages as a water bed draining pump, known venturi pump constructions are difficult to use with a water bed. Among other things, known venturi pumps are difficult to connect to water beds and must be stored when not in use. These inconveniences have adversely affected the acceptance of venturi pumps for use as water bed drain pumps. Currently the water bed industry is striving to make water beds more user friendly. Accordingly, a premium is placed on user convenience. For these reasons, a water bed with an easy to use venturi pump would be desirable.
The present inventor's previous patent application Ser. No. 07/818,764 filed Jan. 8, 1992, now U.S. Pat. No. 5,136,739 addressed many of these problems by providing a water bed with a built-in drain pump. The pump of that application was preferably a venturi pump that works on the principle that different flow velocities produce different amounts of suction. The bed is fitted with two distinct connections instead of the current one. The second connection remains capped during filling. For draining, however, hoses are attached to both connections. One hose provides a supply of pressurized fluid to the venturi and the second connection allows fluids to discharge.
The bed includes a water-tight bladder having a water tight interior. An inlet port or valve is provided to allow fluid to flow into the interior of the water tight bladder. An outlet port or valve is provided to allow fluid to flow out of the port or valve. A fluid inlet pipe extends into the interior of the water tight bladder from the inlet port. A fluid outlet pipe extends into the interior of the water tight bladder from the outlet port. The distal ends of the inlet and outlet pipes are preferably coaxially aligned. A nozzle is provided in the end of the inlet pipe and a diffuser is formed in the end of the outlet pipe. The nozzle and diffuser are maintained in alignment by a spacer member provided in the interior of the water tight bladder. The spacer member may be of any convenient form, but is preferably formed with openings or elongated slots such that spacer member acts as a filter to prevent clogging of the fluid passages. A filter mesh may be provided to enhance this effect. The venturi pump may be formed as a one-piece element adapted to be inserted into either the outlet pipe or, preferably, the inlet pipe.
The invention described in the previous application is particularly well suited for retrofitting existing bed valves and adapters with an in-bed pump. There remains a need, however, to reduce cost and provide a more compact unit.